If you really want more in-depth explanations of car form and function, I recommend Auto Fundamentals by Stockel & Johanson. If you want to go a step further in auto repair I suggest picking up a Haynes Repair Manual specific to your car. Making friends with a veteran mechanic helps, too. =)
It's a good primer and goes through the systems but it recommends more often than not to seek professional help.
You're also better off just getting the service manual of your car from Chilton and Hayes if you want to fix your car. See if you can find this book in the library or bookstore and just browse through the pages in an hour or two. It's definitely not worth having in your library.
